1. Field of Invention
The present invention relates to a magnetic component. More particularly, the present invention relates to a magnetic core.
2. Description of Related Art
A regular magnetic component, such as an inductor or a transformer, comprises a magnetic core generating a closed magnetic loop, and a set of winding coil winding on the magnetic core. Examples of traditional magnetic components 10 are shown respectively in FIG. 1A to FIG. 1C. The magnetic component 10 comprises a magnetic core 20 and a set of winding coil which winds on the magnetic core 20. The magnetic core 20 comprises a plurality of magnetic columns 22 and a plurality of magnetic covers 24 for connecting the magnetic columns for inducing the closed magnetic loop. The magnetic covers 24 are parallel to each other and placed in opposed sides of the magnetic column 22. The magnetic core 20 has a magnetic flux direction M, which passes the left, right columns 22 and top, bottom magnetic covers 24 to induce the magnetic loop. The magnetic component 10 also comprises a set of winding coil 30, winding on the column 22.
A conventional magnetic core 20 is often made by a uniform-filling method. The so-called uniform-filling method means that the magnetic core 20 is composed of a same magnetic material at the cross section perpendicular to the magnetic flux direction M. For example, the magnetic core 20 can be composed of a single kind of magnetic material, as shown in FIG. 1A, or can be composed by two kinds of magnetic material connected in parallel at always, as shown in FIG. 1B, or by two kinds of magnetic material connected in series, as shown in FIG. 1C.
Since the magnetic permeability of a magnetic material decreases with an increase of magnetic field intensity, generally speaking, the inductance of reactor or inductor would decrease along with a DC-bias current applied increasingly. In case of the DC component of load current is in a significant amount, Better DC-bias characteristics could keep a higher inductance and a less variation between the initial inductance (i.e., the inductance when a current of zero passes an inductor) and the inductance under the DC-bias current. As such, it becomes a challenge to retain the better DC-bias characteristics in the case that a DC component of a load current is in a significant amount.